const symid = Symbol('productno')
interface Product {
    [symid]: number | string,
    name: string,
    price: number,
    account: number,
    buy(): string
}

type A = Product["price"]
type B = Product["name" | "price"]
type S = Product[typeof symid]


type PKeys = keyof Product //"name"|"price" |typeof symid |"account"|"buy"
let pKeys:PKeys = "account"

type AllKeys<T> = T extends any?T:never
type PKeys2 = AllKeys<keyof Product>

export { }